The present invention relates to fluid control devices which are adapted, for example, for use in apparatus for manufacturing semiconductors and which require passage of a first fluid therethrough and subsequent replacement of this fluid by a second fluid.
Fluid control devices comprise various components, such as filters, pressure regulators, various kinds of valves, massflow controllers, pressure gauges and pressure sensors, which are connected together. For example as shown in FIG. 5, a pressure gauge 40 is provided generally at the terminating end of a branch channel 42 extending from a main passageway 41 at right angles therewith.
With this conventional fluid control device, the branch channel having its terminating end closed with the pressure gauge provides a so-called dead volume, and with a fluid remaining in this portion of dead volume, another fluid is subsequently passed through the passageway. It is an important problem to reduce the replacement time involved in this procedure and taken for the purity of the subsequent fluid to reach a required value. Consideration is therefore given to how to diminish the dead volume. However, no consideration whatever has been given to the relation between the main passageway and the branch channel relative to each other.
An object of the present invention is to provide a fluid control device wherein consideration is given to the position of passageways relative to each other so that one fluid can be replaced by another within a shortened period of time.
The present invention provides a fluid control device comprising a first passageway, and a second passageway communicating therewith and having a terminating end closed with fluid control means, the first passageway being adapted to pass a fluid therethrough with a different fluid remaining in the second passageway, the fluid control device being characterized in that the first passageway comprises an upstream portion and a downstream portion communicating with the upstream portion at an approximate right angle therewith, the second passageway extending from a terminating end of the upstream portion of the first passageway in alignment with the upstream portion.
Useful fluid control means include a measuring instrument, such as a pressure gauge or pressure sensor, closing the terminating end of the second passageway at all times, and a channel opening-closing device, such as is provided by a valve, for temporarily closing the terminating end of the second passageway.
The fluid control device of the present invention has the feature that the second passageway providing a dead volume in replacing one fluid by another extends from the terminating end of the upstream portion of the first passageway in alignment with the upstream portion, whereby the time required for the replacement of fluid can be shortened without diminishing the dead volume.